This invention relates to a machine for treating a road surface or the like, and in particular but not exclusively, to a machine for forming lateral grooves in a road surface.
In recent years it has been appreciated that it is cheaper to form a grid of grooves in a road surface, when it becomes polished by use, rather than providing a new surface. In addition, there are other operations such as preparing large areas of flooring for surface treatment which require such sets of grooves. To date the lateral grooves in the grid are formed by passing cutting machines over the surface. These can only treat a narrow width and require steering and operation by an operator. Thus to treat any reasonable sized area or a road surface a great deal of manpower is required. This is particularly important as jobs have to be completed quickly to avoid disruption to traffic.
It is an object of the present invention to provide an improved machine for treating a road surface and in particular, but not exclusively, a machine for forming grooves in such a surface.
F-R-A-2,516,109 describes a machine for treating a road surface comprising a wheeled main frame for movement in a first direction, a wheeled sub-frame carrying a treatment head mounted on the main frame for transverse movement thereon and lifting means for raising and lowering the sub-frame for moving the treatment head into and out of engagement with the road surface.
The invention consists in a machine for treating a road surface or the like including a main frame or chassis, a treatment head mounted on the frame, first means for moving the frame in a first direction with the treatment head lifted from the surface and means for engaging the treatment head with the surface characterised in that the machine further comprises second means for moving the frame in a second, generally transverse, direction with the treatment head acting on the road surface and with the first means lifted thereform.
The main frame may be wheeled for movement in a first direction, and the machine may further comprise a wheeled sub-frame mounted on the main frame for movement in a second direction, lifting means for raising and lowering one of the sets of wheels such that the machine may be moved in the first or second direction as selected and a surface treatment head mounted on the sub-frame.
It is preferred that the lifting means raise and lower the sub-frame wheels and they may simultaneously raise and lower the treatment head such that it contacts the surface only when the sub-frame wheels contact the surface. Conveniently there are a plurality of side-by-side treatment heads mounted on the sub-frame and each may be pivotally mounted. In this case the means for raising and lowering the treatment head may comprise a member extending between the pair of sub-frame wheels for engaging the heads or an extension thereof such that as the sub-frame wheels are lifted so are the treatment heads. Each treatment head may be a grooving head and may include spray means for spraying water onto the surface of the road being treated.
In a preferred embodiment there are two side by-side sub-frames, each carrying a set of wheels and a set of treatment heads, the treatment heads on one sub-frame being aligned with those on the other sub-frame in the second direction.
The machine may further comprise adjustment means for altering the position of the sub-frames along the second direction with respect to the main frame and in particular the adjustment means may be arranged to alter the separation of the two sub-frames.
The machine may comprise control-means for operating the machine on the following cycle:
Moving the machine forward along the first direction of movement on the main frame wheels, engaging the sub-frame wheels on the road surface and lifting the main frame wheels therefrom, driving the machine and hence the treatment heads in the second direction, lifting the sub-frame wheels and lowering the main frame wheels to advance the machine in the first direction.
Preferably the movements in the first direction are alternatively a first distance and a second distance, the first distance being equal to the separation of the treatment heads on the sub-frame and the second distance being equal to the total span of the heads taken in the first direction.
The main frame wheels may be hydraulically driven and the machine may further comprise an automatically operated dump valve for returning the hydraulic fluid to a tank when the required distance has been travelled. The main wheels may also be provided with fail-safe brakes which engage when the hydraulic fluid is dumped.
The invention may be performed in various ways and specific embodiments will now be described, by way of example, with reference to the accompanying drawings, in which:
A machine for forming lateral grooves in a road surface is illustrated in Figures 1 to 3. The machine, which is generally indicated at 10, essentially comprises a wheeled main frame 11 on which are mounted two lateral wheeled sub-frames 12 which carry grooving treatment heads 13. As will be explained in detail below the wheels 14 of the sub-frames 12 are vertically adjustable so that they can be engaged or disengaged from the road surface 15 such that in their disengaged position the main frame wheels 16 lie on the road surface, whilst in the lowered position of the sub-frame wheels 14 the main frame wheels 16 are raised from the road surface 15 as shown in Figure 2.
Thus the machine 10 is capable of being driven in a first direction, indicated by the arrow 17 on the main frame wheels 16 and driven in a second direction, indicated by the arrow 18, on the sub-frame wheels 14. When being driven in the second direction 18 the treatment heads 13 engage the road surface 15 and groove it. Hence (as is best seen in Figures 5 and 6) the machine 10 could start off with its one set of grooving heads 13 adjacent the white line 19 on a road surface and be driven over to the verge 20. The machine 10 is then lowered onto its main frame wheels 16 and advanced by the distance equal to the separation of the grooving heads 13 in the first direction. The machine 10 is then returned to its sub-frame wheels 14 and driven back to the white line 19 grooving into the gaps 21 in the pattern. The machine is then advanced, on the main frame wheels 16, by the full distance of the span 22 of the grooving heads and another sequence is initiated.
Turning now to the construction of the machine 10 in more detail, the main frame 11 is a rectangular box-section frame having lateral rods 23 extending adjacent either end between its side members 24. The sub-frames also comprise a generally rectangular box-section frame and are mounted onto the main frame by means of respective blocks 25 mounted on each of the lateral rods 23, the blocks 25 being engaged by upstanding arms 26 on the sub-frame 12. The blocks are a tight fit on the lateral rods 23 and generally allow no movement of the sub-frames, but the separation of the sub-frames 12 can be altered by means of a threaded rod 27 which engages in oppositely threaded holes in the blocks 25. The rod 27 is turned by means of a sprocket 28 and a chain drive 28a which is in turn operated by a hand wheel 29.
The construction of the sub-frame 12 is identical, although oppositely handed, and only one will be described. As can be seen in Figures 1 and 2 the sub-frame defines five grooving head mountings 30 at spaced positions along its length. A grooving head 13 is pivotally mounted to each mounting and includes a grooving wheel 31, and a height adjustment wheel 32. The grooving wheel 31 is driven from a drive shaft 33 (see Figure 3) by means of a drive belt 34 and pulleys 35 and 35a. The drive shaft 33 includes flexible couplings 36 between each mounting 30 and the shaft 33 extends along the pivot axis of the grooving heads 13. Each body 37 of the grooving heads 13 carries an upside down hook 38.
The sub-frame wheels 14 are mounted on pivot arms 39 which can be raised and lowered by means of hydraulic rams 40. The wheels 14 on one sub-frame are driven and those on the other are not. However, in each instance the wheels are interconnected and fixed to a shaft 41 which passes along the length of the sub-frame 12 beneath the hooks 38 such that when the wheels 14 are raised by the hydraulic rams 40 the grooving heads 13 are also raised.
As can be seen from Figure 1 the leading main frame wheels 16 are mounted at spaced positions, whilst the trailing pair are mounted on a pivotable bogie steerable by means of a tiller 42. The main frame 11 has a deck 43 on which is mounted an internal combustion engine 44 which drives hydraulic pumps located in the housing 46.
Figure 4 shows, schematically, the details of the hydraulic circuit. The circuit includes five motors: the first two, 47 and 48 drive the main shaft 49 of the leading main frame wheels 26; the next two 50 and 51 drive either end of the drive shaft wheels and the final, lifting motor, drives the common shaft 41 of the driven pair of sub-frame wheels.
The power for motors 47, 48, 50 and 51 is provided by pump 53 which pressurises a line 54 supplied to a multiple valve 55 through a filter 56. The valve is arranged so that motors 50 and 51 are driven at precisely the same speed, but motors 47 and 48 can be driven at different speeds to assist steering.
A gear pump 57 pressurises a line 58 which is supplied to thee sub-frame wheel motor 52 and to the hydraulic rams 40. The supply of this fluid is controlled by a two-position valve 59. Each of the pumps 53 and 57 is driven by the engine 44.
The valves 55 and 59 are controlled by an electrical control 62. This is also fed by a tachometer 60 which detects the forward movement of the machine 10 in the first direction 17. By making the separation between the grooving heads 13 the same width as the grooving heads, the span is a multiple of the separation distance. Thus if the tachometer is arranged to produce an output every separation distance, say 200 millimetres, then the control circuit counts the first of these and brakes the machine by using the dump valve 63 to dump the fluid from the motors 47 and 48 to tank 64 as described above. The lateral grooving movement of the machine then takes place and after that the machine 10 is advanced until another nine outputs from the tachometer have been recorded. The machine is then stopped again and the cycle is repeated.
It will be appreciated that the above machine is virtually fully automatic in operation and only requires a single operator to steer the forward movement in the first direction 17. It is therefore very cheap on manpower and because of the large number of heads operates relatively quickly. The machine can be constructed in many different ways provided that it is capable of controlled forward movement in the first direction and intermediate lateral grooving movement.
It should be noted that the grooving wheels 31 on the sub-frame 12 rotate in the opposite direction to those on the other sub-frame. This arrangement counters a tendency of the grooving wheels to run away and removes the necessity to provide heavy braking capabilities.
Spray means, one of which is shown at 61, are provided to spray water onto the road surface 15 when the heads 31 are operating.